Temporal Dynamic Modeling for the Assessment of Water Availability and its Effects on Sustainability of Water Resources at Boi Branco Sub-basin, SP, Brazil

This study aimed at developing a Dynamic System (DS) Model to assess the sustainability of the use of water resources in the sub-basin of Boi Branco over a 10- year time frame (2011-2021). Intensive irrigated agriculture occurs in the area, mostly using center-pivot irrigation. Simulations to determine the water supply, demand and sustainability index were performed under three scenarios involving: 1) 75% and 50% precipitation probability, and irrigation system efficiency, 2) 75% and 50% precipitation probability, and environmental flow of 1/40 and 1/10 of the mean pluriannual flow, and 3) same rainfall pattern as observed between 1971 and 1980. Our results show that water demand is greater than potential surface water supply, reflecting vulnerabilities that allow classifying the condition of the sub-basin as critical, in accordance with Article 14 of Law 9034.